Poor purity can cause patients to experience fever, chills, nausea, skin irritation, infections and low blood pressure.

Zealand Pharma CEO Adam Steensberg said Friday that the company is working on a next-generation weight loss drug that’s designed to work differently from those currently on the market and with the potential for fewer side effects.

Peptide companies' are creating knock-off versions of these drugs that have not been approved by the FDA and contain ingredients that may lack the purity of the branded medications.